Model pengendalian pencemaran air pada Wilayah Kali Surabaya

Abstract

Kali Surabaya merupakan bagian hilir (downstream) dari sungai Brantas yang mengalir dari Dam Mlirip hingga pintu air Jagir. Keberadaan Kali Surabaya sangat penting bagi keberlangsungan perekonomian dan kelangsungan hidup bagi masyarakat, industri, pertanian, dan niaga di sekitar bantaran kali serta sumber air baku PDAM Kota Surabaya. Peningkatan pembuangan limbah domestik dan industri di sepanjang Kali Surabaya telah menyebabkan penurunan daya dukung dan daya tampung Kali Surabaya. Kondisi ini jika dibiarkan akan menimbulkan dampak ekologis, ekonomis, dan sosial bagi masyarakat dan membutuhkan biaya pemulihan yang lebih besar. Karenanya, upaya pengendalian pencemaran air Kali Surabaya perlu dilakukan secara baik. Tujuan utama penelitian ini adalah untuk membangun model pengendalian pencemaran air Kali Surabaya. Penelitian dilakukan dalam lima tahap, yaitu (1) menentukan kondisi eksisting parameter fisik kimia perairan Kali Surabaya, (2) menentukan beban dan tingkat pencemaran, (3) menentukan prioritas kegiatan reduksi beban pencemaran dan teknologi pengendalian, (4) membangun model dinamis pengendalian pencemaran air, dan (5) merumuskan kebijakan atau skenario pengendalian pencemaran air Kali Surabaya. Penelitian dilaksanakan dengan cara survei lapangan, pemeriksaan contoh secara langsung di lapangan dan di laboratorium, penyebaran angket, dan wawancara mendalam dengan pakar. Metode yang digunakan untuk menentukan beban pencemaran adalah rapid assessment. Status kualitas air dan tingkat pencemaran dianalisis dengan metode STORET dan indeks pencemaran, sedangkan prioritas kegiatan reduksi beban pencemaran dan teknologi pengendalian dianalisis dengan metode analytical hierarchy process (AHP) dan comparative performance index (CPI). Model pengendalian pencemaran air Kali Surabaya yang terdiri atas tiga sub-model, yaitu (1) sub-model ekologi, (2) sub-model ekonomi, dan (3) sub-model sosial, dibangun melalui pendekatan sistem menggunakan program powersim versi 2.5, sementara penyusunan skenario berupa rancangan kebijakan pengendalian pencemaran dikembangkan dengan menggunakan analisis prospektif.

The Surabaya River plays an important role as water supply of the Surabaya PDAM, irrigation, industry, transportation, and means of recreation. However, domestic, industrial, and agricultural waste that were discharged into the river stream polluted the Surabaya River and decreased the carrying capacity and assimilative capacity. Therefore, effort to monitor and control the Surabaya River water pollution need to be well organized and implemented. The aim of the research is to develop a model of water pollution control on Surabaya River region. The research was conducted in five steps, i.e. (1) determine the existing condition of physical and chemical parameters, (2) determine the load pollution and level of pollution, (3) determine the priority of reduction activities of loading pollution and technology control, (4) build dynamics model of water pollution control, and (5) formulate policies or scenarios of water pollution control of the Surabaya River. The research was carried out based on field survey, in situ and laboratory sample examination, questionnaire, and expert judgement. The loading pollution was determined by rapid assessment. The STORET method and pollution index were used to determine the water quality status and level of water pollution. Analytical hierarchy process (AHP) and comparative performance index (CPI) were used to determine the priority of reduction activities and technology control. Pollution control model developed in this study was built into three sub-models, namely: (1) ecology sub-model, (2) social sub-model, and (3) economy sub-model using powersim constructor 2.5 version. Pollution control scenarios were developed using prospective analysis. The results of water pollution parameters such as total suspended solid (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrite (N-NO2 Keywords: pollution control, prospective analysis, surabaya river, system approach ), and the level of mercury (Hg) were higher than the allowable class 1 standard. The sources of Surabaya River pollution mainly are domestic and industrial waste with total load of BOD, COD, and TSS are 55.49, 132.58, and 210.13 ton/day, respectively. According to water quality status, the Surabaya River is categorized as heavy polluted and the loading pollution need to be decreased. Simple management and efficiency are mainly criteria for reduction activities of loading pollution with determining water class as top alternative following with illumination and calculated the carrying capacity toward water pollution load. The wastewater garden, filtration, screening, and biofilter are priority of technology control in sequence. By using prospective analysis, there were five important factors that affect the future of the Surabaya River water pollution control, i.e.: (1) population growth and community awareness, (2) community perception, (3) implementation of regulations, (4) commitment/local government support, and (5) system and institutional capacity. There are three development scenarios, that are pessimistic, moderate and optimistic. The moderate and optimistic scenario are the realistic scenarios that occur in the future for Surabaya River water pollution control in considering of ecology, social and economy aspects.